It may or may not be the same ECO, but even if it is a different one they will be aware of you previous refusal and should follow the same guidelines.
If you mean that you want to work in the UK after you have finished studying than that may be difficult anyway if you are only going to study for NVQs. If you mean you want to start working now then that really is a problem, the only reason for a applying for a student visa should be that you want to study. If the ECO thinks you are only applying for a student visa so you can work you are likely to get refused.
